Multifluid manifold



March 1950 s. HOLM ET AL.

MULTIFLUID MANIFOLD 2 Sheets-Sheet 1 Filed April 16, 1947 NITROGEN OXYGEN EmoEE Ems: .4.

INVENTOR. Jren f/o/m BY Per A/l/mrrfl ar/ssoxr WARM All? March 7, 1950 s. HOLM ET AL. 2,499,384

MULTIFLUID MANIFOLD Filed April 16, 1947 2 Sheets-Sheet 2 [1.4 /7// 154 I I A 1214 ORNEY Fatentedl Mar. 7, 1950 UNITED MULTIFLUID MANIFOLD Sven Holm and Per Hilmer Karlsson, Wellsville,

N. Y., assignors to The Air Preheater Corporation, New York, N. Y.

Application April 16, 1947, Serial No. 741,879

2 Claims. 1

The present invention relates to heat exchange apparatus and particularly to an exchanger in which heat is transferred among three or more streams of fluid.

The apparatus may be utilized to cool air to very low temperatures using oxygen and nitrogen, both at temperatures substantially below 0 F. The air entering at a temperature around 100 F. carries a certain amount of water vapor wh ch sublimes to ice at low temperatures. To dispose of the ice it is necessary to transpose the air and nitrogen streams so that the nitrogen reevaporates the ice deposited from the air. The apparatus, therefore, works in two cycles, each of which must give the same performance as to heat exchange and pressure drop.

In the embodiment of the invention shown the heat exchanger is a plate type having a plurality of concentric annular passages with several of these allocated to each of the fluids being treated. With such a heat exchanger it is necessary to provide for admitting and discharging a fluid from several annular or semi-circular passages which are spaced radially of the apparatus from each other. tinuous flow requires special formation of inlets and outlets for the various passages and a feature of the present invention is a manifold suitable for use in such a heat exchanger whereby the difierent fluids may be distributed among a number of radially spaced passages while at the same time fluids that flow in one series of passages in one cycle of operation of a process may be directed through another series of passages in a subsequent cycle of a process.

The invention will be best understood upon consideration of the following detailed description of an illustrative embodiment thereof when read in conjunction with the accompanying drawings in which:

Figures 1 and 2 are plan and elevational views respectively of a pair of heat exchangers embodying the invention and arranged to carry out a process where switching of fluids is required in difierent cycles of operation.

Figure 3 is a transverse sectional view through manifold connections at one end of a heat exchanger shown in Figure 2 providing for the admission of one fluid and the discharge of another from this end of the exchanger.

Figure 4 is a corresponding sectional elevation on the line 4--4 in Figure 3.

This application is a continuation-in-part of an application filed in our names on November 3, 1944, under Serial No. 561,766.

To provide for substantially con- In the copending application there is disclosed a heat exchanger in which gas and air streams are circulated through concentric passages while oxygen flows through an adjacent annular channel so that heat exchange occurs to cool the air streams. Several groups each including three passages through which these fluids are circulated are combined in a singular apparatus so that a number of the streams of the various fluids are in heat transfer relationship at the same time. In order that the desired switching of the fluids to accommodate a particular process may occur, two heat exchange units may be employed suitably interconnected by piping with appropriate valves as disclosed in a later application Serial No. 643,331, filed January 25, 1946, so that while nitrogen flows through certain groups of passages in one cycle of operation and air through another group of passages while the second cycle of operation may have the air flowing through passages previously traversed by nitrogen and vice versa.

Each of theheat exchangers designated A or C in Figs. 1 and 2 comprises as shown in Fig. 3 a plurality of concentric wall members ll, [2, l3 and I4 defining a pair of adjacent annular passages IS, IS extending from end to end of the apparatus and located outwardly of a channel l'l. Additional groups of passages designated by the same numerals with the suifixes Aor B increase the capacity of the apparatus. One of the cooling fluids (oxygen) enters the channels l1 through an inlet connection 20 at one end of the apparatus and is discharged from the opposite end of the exchanger through an outlet connection l9 (Fig. 2).

The cold nitrogen enters the top of the apparatus A through an inlet connection 30 which extends toward the center of the apparatus in alinement with sleeves 22 (Figs. 3, 4) that pass through the oxygen and air annuli IS, IT, l5A, l'lA where necessary so that nitrogen enters only the second, fifth and eighth or every third annulus counting from the second i. e. annuli "5, ISA, (6B. At the lower right hand side of the apparatus (Fig. 2) the nitrogen is discharged through a similarly connected outlet 3E| which communicates only with the lower ends of the annuli IE, ISA, IBB.

At the lower end of the apparatus A air to be cooled enters 0n the left hand side through an inlet connection 21 and flowing upwardly through the outermost annular passage l 5 and the fourth and seventh annuli I5A, I5B passes by sleeves 22 penetrating the second and third, fifth and sixth.

annuli to the outlet connection 24 at the upper end of the apparatus.

Oxygen entering the apparatus through pipe connection passes into the header chamber 4! above plate and flows downwardly through the annular channels l1, l'lA between the stream of nitrogen and air in their respective passages, the oxygen eventually entering a similar off take header at the bottom of the apparatus.

With connections so arranged the air flows countercurrent with respect both to nitrogen and oxygen, which is the desired relationship for maximum heat transfer. As shown each of the passages l5, I6 is annular but these annuli could be subdivided, if desired, as disclosed in the parent application. As described herein, the center space within the wall l4 isnot utilized as a heat exchange passage.

Fundamentally the apparatus comprises a plurality of adjacent parallel fiuid passages. In the form described these are in groups of three concentric circular annuli. It may be noted that if no special provisions were made and the air were to flow in the outer annulus [5 in cycle I and then in the intermediate annulus H1" in cycle II, it is evident that the air would be cooled to a much lower temperature in cycle II, where it would flow between the cold oxygen in channel ii and the cold nitrogen in passage [5. The discrepancies in the diameters of the annuli could also result in a difierence in pressure drop due to difference in mass velocity.

In the first cycle of operation with the valves 53; 5| (Fig. 2) 5'2, 53 Open and the valves 54 to 5? closed, air to be cooled passes from the supply duct l0 through valve 5| and inlet 2! to the lower ends of the passages [5, ISA, |5B in the exchanger A and from the outlet connection 241A at its upper end, conduit 80 (Fig. l) and the inlet 336A at the upper end of unit C through its passages IE, [6A, 6B and via outlet 3| at the bottom and Valve 52 to the cooled air line H. At. the same time the exchanger C'is supplied with cool nitrogen from line 12 through valve 50 and inlet connection 2| which flowing upwardly through the passages l5, I5A, [53 thereof is discharged via outlet 24 and conduit 8| to inlet on unit A flows downwardly through its passages l5, l6A, 16B and through the outlet connection 3! and valve 53 into the warm nitrogen-line l3. Simultaneously the stream of cold oxygen fiows into the right hand heat exchanger C through the inlet connection I9 passesupwardly through the passages ll, HA, located between those through which the streams of nitrogenand air are passing to be finally carried from the outlet connection 20 through the pipe 82 to the inlet 29 of the oxygen passages at the upper end of the heat exchanger A and passing downwardly through the passages ll, HA of the latter is finally dis charged from outlet connection l9 into the warm oxygen line.

In the second cycle of operations the positions of valves to 51 are reversed so that in both exchangers A- and C nitrogen flows through pas sages previously traversed by air (as it, A in unit A) while air flows through those passages (as l6, [BA in unit A) throughwhioh nitrogen. passed. In both cycles of operation the stream of oxygen flows in a single direction.

The manifold construction providing for the admission and. discharge of the three different fluids at opposite ends of the radially spaced annular passages. as l5, IEA, I5B in each group is shown in Figures 3 and 4. The eight annular the heat exchanger illustrated are defined as described above of nine concentric wall members H-M, llAl4A and HB which consist of a plurality of nested cylindrical tubes of appropriate diameter. The walls of the cylinders are formed as at diametric points with ports for admission and discharge of the various fluids. to and from the annular passages formed between the concentric tubes. As will be noted in Fig. 4, the lengths of the various cylinders forming the annular passages increase progressively from the center of the apparatus towards its outer boundary.

In constructing the apparatus the shortest and innermost tube HE is closed somewhat inwardly of its extreme ends by plates 25 welded in place at 26. The two next larger and progressively longer tubes MA and ISA are then placed over and around the tube I [B with the fluid ports in their walls aligned. The, ports are shown in Figs. 3' and 4 on the left hand side at the upper ends of the tubes I3A, MA. The end portions of the first and second tubes l IB and MA which are belled or'outwardly flared at 21, 28 are joined to the tubes MA, l3A respectively by welds 29, 32. The flared portions 21, 28 thus close the outer ends of the passages I'BB; I5B between the tubes HB and [3A and between the latter and tube MA. By flaring the ends of the tubes the use of additional annular shaped end closures to fill these gaps and two extra welds therefor are eliminated.

The next step is to mount and Weld in place parts'of the innermost left hand sleeve 22A that overlies passages 15B, llA, these being a short sector-shaped plate33 and two side plates 34 all located on the left side at the radial positions of the ports in the walls of tubes HA, !3A. These plates attached by welds 36 to 39 form the bottom or baseand sides or" the port for the admission and'discharge of fluid to thetinnermost passage IGB. These plates close ofithe passages HA. IE3 at the location of the port along its base and sidessothat there is no flow between these two passages and inlet 30'; they do not, however, block axial flow in these passages because the fluids may'flow around the built-up sleeve 22A which occupies only a small sector of the circumference ofv the passages. At the upper end of tubes [3A, 92A the weldjointASKFig. 4) therebetween extends only for the width of the fluid ports in the walls of the tubes and hence does not shut off How from passage HA into header AL. The plates 33, 34 being welded-to tubes MA and 13A the inside welds 31, 39' must be made before assembling the next tube. EA since otherwise it would'becomeimpossible to make. the. weld joints 31 and 39.

Subsequently the fourth tube IZA is placed over the three already assembled tubes Ii, MA, 13A and spaced distance pieces 4!} (Fig. 3) are welded between the walls of the tubes I3A and 12A at several circumferentially spaced locations to hold these tubes apart while stillprovidingfor endwise flow of fluid from the annular passage I'IA between the tubes into the oxygen chamber 4| in the intervals between-the distance pieces 40. When this has been done the partial circumferential'weld 42 may be formed between the tube |2A and the outer ends of the port base plate 33 aswell as the welds 43 to the. side plates 34 of the fluid port leading to passage MB. The base plate 33A of the sleeve 22Bdischarge port at the opposite side of the exchanger leading from passage I5B may then be welded to the tubes l2A and 13A and the side wall plates of this port may be also welded in place with weld joints 36A and 31A for the base plate 33A made with the tubes [2A and 13A. These joints must be made before the fifth tube 5 IA is mounted in position around the assembly and circumferential weld 65 formed between the outwardly flared ends Alt of the fourth tube HA and the wall of fifth tube HA. The base plate 33A and side plates 34A of the port sleeve 22B are then welded circumferentiall at ll and longitudinally at 48 to the last assembled tube HA along the marginal edges of the fluid opening in its right hand Wall.

As described thus far, the five tubes HB, MA, MA, MA, and HA reading from the center of the exchanger have been assembled and welded together to form four passages, a complete exchange group of three and one extra of the next group. Port sleeves have been provided so that one fluid, such as nitrogen, may be directed from the left (Fig. 4) into the innermost passage 16B lying between the tubes HB, MA while it is prevented from entering the concentric passages i5B, I'L'A by the plates 33, 34 of sleeve 22A. The nitrogen may also enter passage [6A between the tubes 12A, l IA. Likewise a second fluid may flow at the right to or from passage I5B between the tubes MA, I3A but is kept from innermost passage 1613 by the imperforate wall of tube 14A and from passage llA by the plates 33A, 34A of port sleeve 2213. The third fluid may also pass from header 4! endwise into channel HA between tubes 12A, i3A except at the minor portions where the welds &9 close the tops of the port sleeves 22A at the left and 22B at the right.

Considering the entire assembly of nested tubes thus far formed as the equivalent of the innermost tube NB the sequence of operations is repeated by first mounting the sixth tube M in place and welding at El the flared end parts 60 of the tubes HA to this last assembled tube It, etc., as outlined above.

Finally, the spaces 4! beyond the closure plates of the innermost tube HB are closed by welding in the plates 63 as to the tube 13. Inlet and outlet pipes l9, 2 are welded into central openings in these plates to provide for admission of oxygen to and its discharge from these spaces and to the annular channels ll, "A, that communicate therewith. A sleeve or flange B4 is also welded where necessary to the outer tube H to form the outer boundaries of the ports for admitting or discharging air through the walls of the outermost tube.

Although operations on only the upper end of the exchanger as shown in Figs. 3 and 4 have been described it will be understood that both ends of the several tubes are worked upon so as to provide inlet and outlet manifolds at both ends of the exchanger.

In addition to providing a convenient method of closing off the ends of the air and nitrogen passages the progressively shorter lengths of the concentric tubes also make it possible to pro ortion the inlet and outlets to the volumes of fluid at points radially of these ports. At the outer left side the gas inlet port has an area large enough for all the fluid to be admitted to three concentric annuli l5, IEA and HEB. At the location beyond passage I'5A the area will be seen to decrease since only the passages 15A and I5B remain to be supplied. Further inwardly beyond the location of passage I5A a further decrease in area takes place because only the volume for passage 15B remains to be supplied. Conversely, when functioning as discharge ports the area increases progressively in a radially outward direction as may be noted at the right of Figs, 3 and 4 where the port area adjacent the inner air annulus i513 is about a third of the port area beyond the third air passage [5.

What we claim is:

1. In a multi-fluid heat exchanger of the type described; a plurality of nested tubes spaced to form several groups of concentric passages each comprising a central channel and a passage at either side thereof, said tubes being formed with alined port openings at circumferentially spaced positions in the walls thereof; inlet and outlet connections leading to said ports for fluid admission and discharge to and from said passages, said tubes being of progressively longer lengths proceeding outwardly from the innermost tube with the extreme end portions of certain tubes flared outwardly to contact the outwardly adjacent tube to form closures for the ends of said passages; and fluid tight joints between the flared ends of said tubes and the walls of the adjacent tubes.

2. In a multi-fluid heat exchanger of the type described; a plurality of nested tubes spaced to form several groups of concentric passages each comprising a central channel and a passage at either side thereof, said tubes being formed with alined port openings at circumferentially spaced positions in the walls thereof; inlet and outlet connections leading to said ports for fluid admission and discharge to and from said passages, said tubes being of progressively longer lengths proceeding outwardly from the innermost tube; means closing the ends of the innermost tube to form the inner wall of a header connecting with said channels; and a closure plate provided with a fluid supply or discharge connection spaced axially of said closure and attached peripherally to another tube for forming the outer end of said header.

SVEN HOLM. PER HILMER KARLSSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,615,658 Shipman Jan. 25, 1927 FOREIGN PATENTS Number Country Date 4,832 Great Britain Mar.-3, 1903 6,146 Great Britain Mar. 23, 1901 13,365 Great Britain Nov. 25, 1850 

